Digitizers vs Scopes

Digitizer, Oscilloscope… To-may-to, To-mah-to, right? Yes, at basic level, digitizers and oscilloscopes are very similar. They both convert analog signals to a digitized signal using an ADC (analog-to-digital converter). However, they have very distinguishing characteristics that are driven by the use-case or applications they address.

Let’s start with oscilloscopes. Oscilloscopes are primarily designed as visualization and trouble-shooting tools and serve a very broad market. Oscilloscopes commonly feature a large screen with a robust graphical user interface, as shown in figure 1. They are designed for interactive test and analysis and include a variety of triggering types (i.e. edge, glitch, pulse width, runt, timeout, zone qualified, etc.), sophisticated probing solutions (i.e. passive, active, single-ended, differential, current, etc.), and analysis applications (i.e. serial data analysis, jitter analysis, crosstalk analysis, PAM-4 analysis, etc.). One example of an oscilloscope use case is and R&D lab troubleshooting a prototype of a new design that is having intermittent failures. The engineer will want a tool that enables probing various points on the board and allow them to zoom in and out of the signal to see both at a macro view and micro view what is going on. They will also want a tool that enables various range settings and trigger types.

Figure 1: Keysight S-Series 10-bit oscilloscope

Moving on to digitizers. Digitizers are focused on acquisition of data for a specific use. Digitizers tend to be in modular form factor, as shown in figure 2. Modular form factors enable channel density and multi-channel measurements that require synchronization or coherency. Modular architecture enables synchronization and communication with multiple instruments making it a robust form factor for solutions in a small footprint. Digitizers tend to have limited full scale range settings because they are typically designed into a measurement system that does not change. Reducing the number of full scale range settings enables a low noise floor. Digitizers tend to have multiple memory options to enable longer capture times and some digitizers support streaming of data to a RAID array. Furthermore, some digitizers have FPGA’s that are customizable by the end user, which enables real time processing of the incoming data.

Figure 2: Keysight M97xxA family of AXIe digitizers

Digitizers are often found in high energy and shock physics applications which aim to understand how condensed matter responds at extreme conditions. Digitizers are used in conjunction with sensors to both monitor the build of the event and capture details of the event. Channel density and synchronization are key features for this application space. You will also see digitizers in multi-channel applications like phase array antenna measurements and 5G. Not only do these application spaces require channel coherency, they are also increasing in bandwidth requirements. Additionally, digitizers that support FPGA customization enable applications that benefit from real time processing of the data, including, radar target simulation, LiDAR, beamforming, quantum computing, signal monitoring, and larger system test and control.

Need more help determining the differences between oscilloscopes and digitizers? The following resources may help.